Paul Kierstead wrote:
The Word example actually has other worrying problems not mentioned. A Word document contains a lot of hidden information, including other versions. It would be quite easy to sign a Word document that, when you viewed it, looks significantly different then it could be displayed without violating the signature. This is due to numerous problems, the most basic of which is that we often don't sign what we view but instead some binary that we _believe_ represents what we viewed but often does not. This is not just theoretical nor esoteric, but quite easy as the Word example shows.
the answer to THAT is quite obvious, isn't it? I never sign anything that's not plain text. if you put your signature on a multi-page document without opening it, that's your fault. I know the word example is more complicated, and most people have 0.0 clue about those possibilities, but again: that's their problem. don't sign something that you don't understand.